Subsea systems, such as those used in exploration and production of oil and gas, continue to increase in complexity. A subsea well can include sensors and actuators located at or below the sea floor. The sensors can be, for example, pressure sensors, temperature sensors, and erosion detectors. The actuators can be, for example, valves, pumps, and other flow control devices. Information from the sensors is commonly processed by equipment at a surface facility. Similarly, controls for the actuators commonly originate at a surface facility. Accordingly, communication is needed between the subsea devices and equipment at the surface.
Controller area network (CAN) buses are used to interconnect sensors, actuators, controllers, and other devices in applications such as automobiles, industrial automation, and medical equipment. Many circuits and devices have been developed for CAN bus communications. However, current CAN bus based subsea systems face several limitations. Network size is restricted due to the impedance drop that results from connecting multiple electrical devices in parallel. Additionally, conventional driver components may not be suitable for long transmission lines.
There are many types of connectors for making electrical and fiber-optic cable connections in hostile or harsh environments, such as underwater or subsea electrical, optical and hybrid electrical and optical connectors which can be repeatedly mated and demated underwater at great ocean depths. The connectors may be electrical only, optical only, or may be hybrid electrical and optical connectors. These connectors typically consist of releasably mateable plug and receptacle units or connector parts, each attached to cables or other devices intended to be joined by the connectors to form completed circuits. Each connector unit contains one or more electrical and/or optical contacts or junctions for engagement with the junctions in the other unit when the two units are mated together. To completely isolate the contacts to be joined from the ambient environment, one or both parts of these connectors house the contacts in oil-filled, pressure-balanced chambers.
The contacts on one side of a subsea or wet mateable electrical connector are typically in the form of pins or probes, while the contacts or junctions on the other side are in the form of sockets for receiving the probes. Typically, the socket contacts are contained in a sealed chamber containing a dielectric fluid or other mobile substance, and the probes enter the chamber via one or more sealed openings which include seals which exclude seawater and/or contaminants from the contact chamber in the mated and unmated conditions. Such electrical connectors are generally known as pin-and-socket type connectors. One example of an electrical underwater pin and socket connector is described in U.S. Pat. No. 5,645,442 of Cairns and is sold by Teledyne ODI, Inc. of Daytona Beach, Fla. under the name Nautilus®.